CN107684897A - The denitrifier and its methods and applications prepared using river bottom mud - Google Patents
The denitrifier and its methods and applications prepared using river bottom mud Download PDFInfo
- Publication number
- CN107684897A CN107684897A CN201710600494.0A CN201710600494A CN107684897A CN 107684897 A CN107684897 A CN 107684897A CN 201710600494 A CN201710600494 A CN 201710600494A CN 107684897 A CN107684897 A CN 107684897A
- Authority
- CN
- China
- Prior art keywords
- denitrifier
- river bottom
- bottom mud
- prepared
- mud
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
- B01J20/10—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising silica or silicate
- B01J20/12—Naturally occurring clays or bleaching earth
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
- B01J20/04—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising compounds of alkali metals, alkaline earth metals or magnesium
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
- B01J20/28054—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their surface properties or porosity
- B01J20/28057—Surface area, e.g. B.E.T specific surface area
- B01J20/28059—Surface area, e.g. B.E.T specific surface area being less than 100 m2/g
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
- B01J20/28054—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their surface properties or porosity
- B01J20/28069—Pore volume, e.g. total pore volume, mesopore volume, micropore volume
- B01J20/28076—Pore volume, e.g. total pore volume, mesopore volume, micropore volume being more than 1.0 ml/g
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/28—Treatment of water, waste water, or sewage by sorption
- C02F1/281—Treatment of water, waste water, or sewage by sorption using inorganic sorbents
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2220/00—Aspects relating to sorbent materials
- B01J2220/40—Aspects relating to the composition of sorbent or filter aid materials
- B01J2220/48—Sorbents characterised by the starting material used for their preparation
- B01J2220/4875—Sorbents characterised by the starting material used for their preparation the starting material being a waste, residue or of undefined composition
- B01J2220/4887—Residues, wastes, e.g. garbage, municipal or industrial sludges, compost, animal manure; fly-ashes
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/16—Nitrogen compounds, e.g. ammonia
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/30—Organic compounds
- C02F2101/38—Organic compounds containing nitrogen
Abstract
The present invention is included on a kind of denitrifier and its methods and applications prepared using river bottom mud, its method:1) river bottom mud is dried, grind sieving processing after, carry out pickling, grinding, cleaning and drying, obtain sediment particles；2) described sediment particles are calcined, obtains bed mud porous material；3) described porous bed mud material is mixed with sodium salt solution, adjusts pH to 2.5 3.5, vibration, filtering, dry, obtain denitrifier.The present invention can slow down the pressure of river bottom mud recycling, have the advantages of simple to operate, preparation condition is perfect, workable, and nitric efficiency is high.
Description
Technical field
The present invention relates to a kind of utilization of solid waste resource recovery and technical field of sewage, more particularly to a kind of profit
The method that denitrifier is prepared with river bottom mud.
Background technology
Rich in materials such as substantial amounts of organic matter, nitrogen and phosphorous nutrient and heavy metals in river bottom mud, cause river course black smelly
Important " source " and " remittance ".The processing handling problems of bed mud are always solid after the removal and dredging of pollutant in black-odor riverway bed mud
Useless and water treatment field hot issue.Correlative study shows that the black-odor riverway bed mud after dredging is fertile as roadbed, farmland
Material, modified filter material etc., certain recycling effect is played, but also occur some problems in application process：Although 1) dredge
Black-odor riverway bed mud afterwards has certain applications in the materials application such as farmland fertilizer, roadbed field, but usage amount is limited after all, and real
Border effect is unsatisfactory；In addition, after large-scale river bottom mud is dredged, a large amount of bed muds are urgently handled, small-scale farmland fertilizer and
The use of roadbed can not meet the recycling of a large amount of bed muds；2) black-odor riverway bed mud is modified through some means, for water
Treatment industry.But itself there is the pollutant of high level, it is bad so as to directly result in water treatment efficiency, in modifying process
Some parameters, such as solid-to-liquid ratio, pH, temperature optimum proportioning condition it is uncertain, black-odor riverway bed mud recycling can be caused
Cost increase.
Nitrogen can cause the biologies such as pasture and water, blue-green algae as a kind of critical nutrients during eutrophication, excessive nitrogen
Amount reproduction, oxygen in water is largely consumed, cause aquatile hypoxia death, smelly phenomenon black to river course directly affects.
Both at home and abroad remove waste water in nitrogen technology include biological denitrificaion method, chemical precipitation method, chemical oxidization method, membrane separation process, blow-off method and
The treatment technologies such as chemiadsorption, wherein various and cheap and easy to get by denitrifier species made from absorption method, technique is simple, easily
In control as the study hotspot of current denitrogenation technology.
The content of the invention
It is a primary object of the present invention to, there is provided it is a kind of it is new using river bottom mud prepare denitrifier and its method and
Using, technical problem to be solved is the recycling for the effective removal and river bottom mud for achieving Water, from
And it is more suitable for practicality.
The object of the invention to solve the technical problems is realized using following technical scheme.Itd is proposed according to the present invention
It is a kind of using river bottom mud prepare denitrifier method, it includes:
1) river bottom mud is dried, grind sieving processing after, carry out pickling, grinding, cleaning and drying, obtain bed mud
Grain；
2) described sediment particles are calcined, obtains bed mud porous material；
3) described porous bed mud material is mixed with sodium salt solution, adjusts pH to 2.5-3.5, vibration, filtering, dry,
Obtain denitrifier.
The object of the invention to solve the technical problems can be also applied to the following technical measures to achieve further.
Preferably, the method for the foregoing denitrifier prepared using river bottom mud, wherein, what the sieving in step 1) was handled
Mesh number is 100-150 mesh.
Preferably, the method for the foregoing denitrifier prepared using river bottom mud, wherein, the acid in pickling in step 1)
For hydrochloric acid.
Preferably, the method for the foregoing denitrifier prepared using river bottom mud, wherein, the calcination condition in step 2) is
450-550 DEG C of calcining 2-4h.
Preferably, the method for the foregoing denitrifier prepared using river bottom mud, wherein, the sodium salt in step 3) is chlorination
At least one of sodium, sodium nitrate and sodium sulphate.
Preferably, the method for the foregoing denitrifier prepared using river bottom mud, wherein, sodium salt solution in step 3)
Concentration is 0.1-0.4mol/L.
The object of the invention to solve the technical problems is also realized using following technical scheme.Itd is proposed according to the present invention
It is a kind of using river bottom mud prepare denitrifier, be prepared by above-mentioned method.
The object of the invention to solve the technical problems can be also applied to the following technical measures to achieve further.
Preferably, the foregoing denitrifier prepared using river bottom mud, wherein described taken off using prepared by river bottom mud
The specific surface area of nitrogen agent is 13.87-16.32m2/ g, pore volume 9.23-11.38cm3/g。
The object of the invention to solve the technical problems is also realized using following technical scheme.Itd is proposed according to the present invention
It is a kind of using river bottom mud prepare denitrifier application, with it is foregoing using river bottom mud prepare denitrifier in waste water
Nitrogen be removed, it is described using river bottom mud prepare denitrifier nitrogen removal efficiency be more than 88%.
The denitrifier and its methods and applications prepared by above-mentioned technical proposal, the present invention using river bottom mud is at least had
Following advantages：
The present invention carries out calcination processing to river bottom mud, changes the surface morphological structure of sediment particles significantly, makes it more
In vesicular texture, total specific surface area is added；By the modification of river bottom mud, the resource utilization rate of bed mud is added；It is logical
The molar concentration of bed mud sample and inorganic sodium is overregulated, seeks to denitrogenate efficiency highest reaction condition, for the de- of sewage
Nitrogen processing.
Described above is only the general introduction of technical solution of the present invention, in order to better understand the technological means of the present invention,
And can be practiced according to the content of specification, described in detail below with presently preferred embodiments of the present invention as after.
Embodiment
Further to illustrate the present invention to reach the technological means and effect that predetermined goal of the invention is taken, below in conjunction with
Preferred embodiment, to according to it is proposed by the present invention using river bottom mud prepare denitrifier and its methods and applications its specific implementation
Mode, structure, feature and its effect, describe in detail as after.In the following description, different " embodiment " or " embodiment " refers to
Be not necessarily the same embodiment.In addition, the special characteristic, structure or feature in one or more embodiments can be by any suitable
Form combines.
A kind of method for denitrifier prepared using river bottom mud that one embodiment of the present of invention proposes, it includes:
1) river bottom mud is dried, after ground 100-150 mesh sieves, pickling, grinding, cleaning and at 105 DEG C in hydrochloric acid
Lower dry 24h, obtains sediment particles；Wherein pickling can clean bed mud surface ash content；
2) described sediment particles are calcined into 1-3h at 450-550 DEG C, obtains porous bed mud material；Wherein calcining can increase
Add the specific surface area of sediment particles；
3) described porous bed mud material is mixed with sodium salt solution, adjusts pH to 2.5-3.5, vibration 24h, filtering, do
It is dry, obtain denitrifier.
Wherein, the concentration of sodium salt solution is 0.1-0.4mol/L；Sodium salt be sodium chloride, sodium nitrate and sodium sulphate at least
It is a kind of.The addition of sodium salt can form oxide-film during vibration and drying on sediment particles surface, increase denitrifier
Specific surface area.
A kind of denitrifier prepared using river bottom mud that one embodiment of the present of invention proposes, is prepared by above-mentioned method
And obtain；The specific surface area of the denitrifier prepared using river bottom mud is 13.87-16.32m2/ g, pore volume 9.23-11.38cm3/
g。
The application for a kind of denitrifier prepared using river bottom mud that one embodiment of the present of invention proposes, with foregoing profit
The denitrifier prepared with river bottom mud is removed to the nitrogen in waste water, the nitrogen of the denitrifier prepared using river bottom mud
Clearance is more than 88%.
Embodiment 1
A kind of method for denitrogenating agent prepared using river bottom mud that one embodiment of the present of invention proposes, it includes:
1) river bottom mud is dried at 80 DEG C, ground 150 mesh sieve；Ground with pH=1.0 HCl solution cleaning and dipping
Mill, filter and cleaned for several times with distilled water, 24h is dried at 105 DEG C, obtains sediment particles
2) sediment particles are calcined into 2h under 500 DEG C of high temperature, takes out cooling, obtain porous bed mud material；
3) porous bed mud material is mixed with 0.1mol/L sodium chloride solutions, adjusts pH to 3.0, vibration 24h, filtering, do
It is dry, obtain denitrifier.
A kind of denitrifier prepared using river bottom mud that one embodiment of the present of invention proposes, by the method for embodiment 1
It is prepared；The specific surface area of the denitrifier prepared using river bottom mud is 13.87m2/ g, pore volume 9.23cm3/g。
The application for a kind of denitrifier prepared using river bottom mud that one embodiment of the present of invention proposes, with embodiment 1
Using river bottom mud prepare denitrifier the nitrogen in nitrogenous effluent is removed, removal effect is as shown in table 1.
Embodiment 2
A kind of method for denitrifier prepared using river bottom mud that one embodiment of the present of invention proposes, it includes:
1) river bottom mud is dried at 80 DEG C, ground 100 mesh sieve；Ground with pH=1.0 HCl solution cleaning and dipping
Mill, filter and cleaned for several times with distilled water, 24h is dried at 105 DEG C, obtains sediment particles
2) sediment particles are calcined into 4h under 550 DEG C of high temperature, takes out cooling, obtain porous bed mud material；
3) porous bed mud material is mixed with 0.4mol/L metabisulfite solutions, adjusts pH to 3.0, vibration 24h, filtering, do
It is dry, obtain denitrifier.
A kind of denitrifier prepared using river bottom mud that one embodiment of the present of invention proposes, by the method for embodiment 2
It is prepared；The specific surface area of the denitrifier prepared using river bottom mud is 16.32m2/ g, pore volume 11.38cm3/g。
The application for a kind of denitrifier prepared using river bottom mud that one embodiment of the present of invention proposes, with embodiment 2
Using river bottom mud prepare denitrifier the nitrogen in nitrogenous effluent is removed, removal effect is as shown in table 1.
Treatment effects of the embodiment 1-2 of table 1 using denitrifier prepared by river bottom mud to nitrogenous effluent
The above described is only a preferred embodiment of the present invention, any formal limitation not is made to the present invention, according to
Any simple modification, equivalent change and modification made according to the technical spirit of the present invention to above example, still falls within this hair
In the range of bright technical scheme.
Claims (9)
- A kind of 1. method of the denitrifier prepared using river bottom mud, it is characterised in that it includes:1) river bottom mud is dried, grind sieving processing after, carry out pickling, grinding, cleaning and drying, obtain sediment particles；2) described sediment particles are calcined, obtains bed mud porous material；3) described porous bed mud material is mixed with sodium salt solution, adjusts pH to 2.5-3.5, vibration, filtering, dry, obtain Denitrifier.
- 2. the method for the denitrifier according to claim 1 prepared using river bottom mud, it is characterised in that in step 1) The mesh number of sieving processing is 100-150 mesh.
- 3. the method for the denitrifier according to claim 1 prepared using river bottom mud, it is characterised in that in step 1) Acid in pickling is hydrochloric acid.
- 4. the method for the denitrifier according to claim 1 prepared using river bottom mud, it is characterised in that in step 2) Calcination condition is 450-550 DEG C of calcining 2-4h.
- 5. the method for the denitrifier according to claim 1 prepared using river bottom mud, it is characterised in that in step 3) Sodium salt is at least one of sodium chloride, sodium nitrate and sodium sulphate.
- 6. the method for the denitrifier according to claim 1 prepared using river bottom mud, it is characterised in that in step 3) The concentration of sodium salt solution is 0.1-0.4mol/L.
- 7. a kind of denitrifier prepared using river bottom mud, it is characterised in that as the method system described in claim any one of 1-5 It is standby and obtain.
- 8. the denitrifier according to claim 7 prepared using river bottom mud, it is characterised in that described utilizes river course bottom The specific surface area of clay standby denitrifier is 13.87-16.32m2/ g, pore volume 9.23-11.38cm3/g。
- 9. a kind of application of the denitrifier prepared using river bottom mud, it is characterised in that with described in claim any one of 7-8 The denitrifier prepared using river bottom mud is removed to the nitrogen in waste water, the denitrifier prepared using river bottom mud Nitrogen removal efficiency is more than 88%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710600494.0A CN107684897A (en) | 2017-07-21 | 2017-07-21 | The denitrifier and its methods and applications prepared using river bottom mud |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710600494.0A CN107684897A (en) | 2017-07-21 | 2017-07-21 | The denitrifier and its methods and applications prepared using river bottom mud |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN107684897A true CN107684897A (en) | 2018-02-13 |
Family
ID=61152940
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710600494.0A Pending CN107684897A (en) | 2017-07-21 | 2017-07-21 | The denitrifier and its methods and applications prepared using river bottom mud |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN107684897A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102357355A (en) * | 2011-09-16 | 2012-02-22 | 华侨大学 | Preparation method of modified fly ash for treating ammonia nitrogen waste water |
| CN102826818A (en) * | 2012-09-04 | 2012-12-19 | 华东师范大学 | Preparation method for bottom mud brick |
| CN104495960A (en) * | 2014-11-03 | 2015-04-08 | 芜湖市祥荣食品有限公司 | Sodium bentonite processing agent for blue-green algae and preparation method thereof |
| CN106000284A (en) * | 2015-11-12 | 2016-10-12 | 中国环境科学研究院 | Nitrogen controlling material prepared based on lake sediment, preparation method and application thereof |
-
2017
- 2017-07-21 CN CN201710600494.0A patent/CN107684897A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102357355A (en) * | 2011-09-16 | 2012-02-22 | 华侨大学 | Preparation method of modified fly ash for treating ammonia nitrogen waste water |
| CN102826818A (en) * | 2012-09-04 | 2012-12-19 | 华东师范大学 | Preparation method for bottom mud brick |
| CN104495960A (en) * | 2014-11-03 | 2015-04-08 | 芜湖市祥荣食品有限公司 | Sodium bentonite processing agent for blue-green algae and preparation method thereof |
| CN106000284A (en) * | 2015-11-12 | 2016-10-12 | 中国环境科学研究院 | Nitrogen controlling material prepared based on lake sediment, preparation method and application thereof |
Non-Patent Citations (2)
| Title |
|---|
| 李文静等: "NaCl改性沸石对水中氨氮的吸附机制", 《中国环境科学》 * |
| 肖利萍等: "环境矿物改性及对污水中氨氮的吸附试验研究", 《非金属矿》 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104941574B (en) | A kind of inorganic ions modified zeolite composite and its application | |
| CN107601678A (en) | A kind of cities and towns black and odorous water and sediment in-situ quickly administer material | |
| WO2018032831A1 (en) | Residual soil regeneration processing system for contaminated bottom mud in rivers and lakes | |
| CN106866175A (en) | A kind of light porous haydite of boccaro mineral aggregate and preparation method thereof | |
| CN101559353B (en) | Preparation method of zinc chloride modified red mud | |
| CN108440013A (en) | A kind of biological aerated filter ceramic grain filter and preparation method thereof | |
| CN107930584B (en) | Sulfur-doped algae-iron composite material and preparation method and application thereof | |
| CN106268639A (en) | A kind of preparation method of the nano-MgO activated carbon of Adsorption of Heavy Metals | |
| CN106311148B (en) | A kind of charcoal composite material and preparation method | |
| Feng et al. | Production of sorption functional media (SFM) from clinoptilolite tailings and its performance investigation in a biological aerated filter (BAF) reactor | |
| CN107417058A (en) | A kind of river embankment bed mud is modified the method and its application for preparing ecology filler | |
| CN105621786B (en) | A kind of vertical artificial wet land system of upper up-flow for handling agricultural non-point source pollution | |
| CN109967041A (en) | A kind of bimetallic-modified magnetic bio activated carbon adsorbent and preparation method thereof is applied in wastewater treatment | |
| CN107684897A (en) | The denitrifier and its methods and applications prepared using river bottom mud | |
| CN209143753U (en) | A kind of dye wastewater treatment segmented packed bed adsorbent equipment | |
| CN107686156A (en) | A kind of Fenton methods of efficient degradation organic pollutants | |
| JP4007890B2 (en) | Water purification material | |
| CN105948349A (en) | Garden water system water circulating purifying technology | |
| CN112844303A (en) | Water purification sludge/sodium silicate composite adsorbent, preparation method thereof and application thereof in treating ammonia nitrogen in water body | |
| CN109647336B (en) | Composite adsorbent for efficiently removing heavy metal ions in wastewater and preparation method thereof | |
| CN104190355B (en) | The preparation method of porous carbon material and for processing the processing method of oil-polluted water | |
| CN112371085A (en) | Steel pickling sludge modified sludge activated carbon for rainwater treatment | |
| CN105688806A (en) | Method for preparing mesoporous carbon from municipal sewage plant sludge in thermal activation mode and sludge-based mesoporous carbon material | |
| CN112619598B (en) | Water phosphorus adsorbent and preparation method and application thereof | |
| CN104998615A (en) | Charcoal preparation method based on mattress fermented feed and application thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20180213 |
|
| RJ01 | Rejection of invention patent application after publication |